It is known to perform noise reduction processing on video signals to improve perceived image quality by mitigating the effects of noise that typically is present in the video signals. Sources of noise include compression encoding/decoding, which may result in various types of artifacts such as block noise, ringing noise, mosquito noise and transform noise. Other sources of noise may include video capture processing, analog-to-digital conversion, and signal transmission.
Noise reduction processing may be performed after video signal decompression (decoding) for purposes of image quality improvement, and may also be performed prior to transmission or recording, to avoid wasting bandwidth on transmission/recording of artifacts as well as for quality considerations.
Typical kinds of noise reduction processing involve low pass filtering of the video signal. Although generally worthwhile to mitigate artifacts, such filtering may also blur the image to some extent, so that noise reduction processing may entail trading off one type of distortion for another. Computational complexity may also be a drawback in noise reduction processing.